Visual rehabilitation via microperimetry in patients with geographic atrophy: a pilot study

Abstract

Background: Age-related macular degeneration (AMD) is the leading cause of blindness in the western world. As a consequence of AMD, patients develop structural damage that comprises the fovea and subsequently present loss of central vision, low visual acuity and unstable fixation. Contrary to what happens with anti-angiogenic treatment in neovascular AMD, there is currently no definitive treatment to reverse geographic atrophy progression. The aim of this study was to determine the effectiveness of the visual rehabilitation treatment via microperimetry in patients with geographic atrophy.

Methods: Longitudinal and prospective study, 18 patients with areas of geographic atrophy in their eye of better visual acuity were included. Macular integrity assessment (Maia) microperimeter (CentreVue, Padova, Italy) was used to diagnose retinal fixation and sensitivity in these patients. Based on these data and using the training module available in the equipment, the patients underwent visual rehabilitation sessions intended to allow the patient to establish the best possible fixation in the best area of retinal sensitivity. To determine the training effectiveness, the following variables were compared before and after: visual acuity in LogMAR scale with ETDRS charts, reading speed with Minnesota Low-Vision Reading Test (MN Read), average sensitivity threshold in microperimetry; P1 and 95% Bivariate Contour Ellipse Area (BCEA) values were used for fixation stability measurement.

Results: Mean age was 77 years old (65-92). Visual acuity of the trained eye was on average 0.7 versus 0.6 LogMAR (p = 0.006) before and one week after training. Reading speed, using both eyes, was 47 words per minute (wpm) before training and 69 wpm after training (p = 0.04). Average retinal sensitivity was 14.1 versus 14.6 db (p = 0.4). Fixation stability improved with P1 values of 45% versus 51% (p = 0.05) and 95% BCEA values of 43 versus 25 (p = 0.02) before and after training, respectively.

Conclusions: Visual training via microperimetry in patients with age-related macular degeneration is effective in improving fixation stability, reading speed, and visual acuity, measured one week after training is completed.

Keywords: Age-related macular degeneration; Fixation stability; Geographic atrophy; Microperimetry; Visual rehabilitation.

Fig. 1

Right eye microperimetry. Stable extra-foveal fixation with good sensitivity area (green zone) in a patient with myopic maculopathy

Fig. 2

Microperimetry report. Sensitivity map and fixation areas as well as normative scales expressed in colors. Look at extra-foveal fixation used by the patient

Fig. 3

Sensitivity map. Based on this map, the selection of PRT (dark blue dot) is done. The patient is trained in order to direct its fixation to the dark blue dot. The light blue dot is the PRL, which corresponds to the average of fixation points used by the patient

Fig. 4

Change of fixation area used by the patient after training sessions

Fig. 5

a Sensitivity map before training where it can be observed the difficulty in the fixation, PRT is selected in the area where sensitivity is observed. Large ellipse corresponds to 95% BCEA. b Trained fixation during training sessions. c New sensitivity map after rehabilitation, the same evaluated area as (a)